Under the condition that a semiconductor maker and a photomask maker are separated but these are mutually connected with a communication line, the semiconductor maker gives a photomask fabrication schedule information to the photomask maker via the communication line, while the photomask maker fabricates the photomask depending on such fabrication schedule information and delivers the photomask to the semiconductor maker. The photomask maker periodically sends, in the course of fabrication process, a photomask fabrication progress information to the semiconductor maker via the communication line. The semiconductor maker regenerates the photomask fabrication schedule information depending on the photomask fabrication progress information sent from the photomask maker and then transfers the re-generated photomask fabrication schedule information to the photomask maker via the communication line. Therefore, mismatch between fabrication of semiconductor integrated circuit device and supply of photomask can be reduced or eliminated.